I've just been asked to share a room once. I had only been in the company for months, I was 20-something, my room mate was a nice guy of my age and it was my first business trip abroad, so sharing was not a problem. The other person travelling with us was our employer and owner of the company, about 40 years older than us. I would have hated to share the room with him, for sure.
Even before that, while I was still at the University, I got a fab scholarship from a bank in Spain. For 6 weeks, a guy from another town and me got a job at their branch in Miami. All expenses paid, including a rented car and an appartment in Miami Beach. However, it also meant meeting a guy at MAD Airport, and sharing the next weeks with him; not only did we work together, but even shared the same bedroom (2 beds, of course!). It was really, really hard at times and after a week it was like hell, but we eventually found the way to bear each other and 14 years later we are still friends.
But sure, I'd hate to share a room now. No matter how lonely I feel while travelling abroad sometimes, at night I DO want to be on my own.